We have been creating hybrid mutants by constructing global and discreet chimeras between the inner faces of the bradykinin B2 and angiotensin AT1 receptors. For example, we now have a hybrid receptor whose intracellular (IC) face is composed predominantly of ATlaR sequences but which responds to BK and possesses characteristic actions of the ATlaR. Presently, we are constructing the opposite hybrids which bind Ang II but are primarily composed of BKB2R sequences within the intracellular (IC) face of the receptor. Our mutational studies, utilizing both global and single site substitutions within the BKB2R have demonstrated clearly that hybrid receptors with mixed binding characteristics and signal functions can be formed, are also working in a similar manner with the prostaglandin E2 EP2 receptor which activates adenyl cyclase and the AT2 receptor which often opposes the action of the AT1R. The parent grant deals with the approaches discussed above. Our ultimate goal using these approaches is to provide important steps in the control of physiologic malfunctions such as hypertension and fibrosis by making available receptors with the same binding characteristics as the given WT receptor but alternate signal and physiologic functions. For example, with regard to Ang ll function, we hope to ultimately provide recipient cells and tissues with the opportunity to possess not only the WT AT1 receptors but also hybrid receptors which respond to Ang II but signal as BK or perhaps as AT2R. This approach should enable the cell and tissue and the individual to counter the deleterious actions of Ang II on blood pressure and fibrosis. We have worked with mouse ES cells in the past. Now, work with human ES cells will provide us with even greater opportunity to take first steps toward our ultimate goal of genetic engineering of events related to [unreadable] hypertension and fibrosis. The NIH registry # for the hES cells to be used is TE-03. [unreadable] [unreadable] [unreadable]